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insufficient heat

His last weekend I finally put my boiler, (gas fired, Burnhard), on line and had a rude surprise when the house would not get over 66 deg F. I bled all the baseboards and changed out the batteries in the thermostat. no change. The boiler cycles on and stays on , I have some 40' of head pressure, and the makeup v/v is wide open. the low water control is not giving any warnings. there are 3 legs coming out of the boiler outlet one for the basement, one for the 1st floor and one for the 2nd floor. I notice that the circ p/p is hot as is the piping immediately downstream of the p/p. however, as I move farther away from the p/p the piping begins to cool. I can feel no vibration at the p/p nor hear any sound from the p/p when I use a screwdriver as a "stethascope".I believe the circ p/p has gone south, but barring the use of a guage on the discharge side do not know how to be sure. My backround was, (20 years ago), in marine steam engine rooms, (antique 450 lb sectional headers and 900 lb M types with controlled superheat), and so, don't feel to be on 100% solid ground with this. Can the expansion tank possibly be the culprit?I hope someone out there can offer a little insight . Thanks


  • Jamie Hall
    Jamie Hall Member Posts: 22,947
    The tank may be giving some problems -- unless you are in a very tall house, 40 psi is considerably more than needed. Does the pressure change much going from system cold to system hot?

    That said, though, I expect you're right -- the circulator isn't circulating. Now the question is -- is it the circulator not getting power to run, or is it dead? First thing I'd check is to make sure that the circulator is really getting power.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    JUGHNE Member Posts: 11,021
    OP mentioned he had 40' of head pressure, if reading the altitude portion of the gauge then would have about 17 PSI, which would be more reasonably correct.

    Walkinman, do you have a 3-piece pump with mechanical coupling or sealed one piece?
    Some sealed units have a large screw plug on motor end which lets you rotate the shaft with a screwdriver. Sometimes they need a bump start.